The traditional and conventional process adopted for conversion of solid organic materials into carbon is by partly or wholly under exothermic condition. The process for conversion of solid organic materials into carbon varies from vertical retort batch processing type to rotary kiln batch or continuous processing type. Such types of processing are partly or wholly under exothermic condition. Also, such type of exothermic process involves a two-step process:
(a) The first step involves carbonization of the solid organic materials (i.e. raw materials) under partial oxidation condition.
(b) The second step involves activation of the carbonized material upon reaction with steam under partial or wholly exothermic condition in another similar vertical retort or rotary kiln.
The disadvantages for the above-mentioned type of processing are as follows: (a) Carbonization of solid organic materials (i.e. raw materials) either in a vertical retort or rotary kiln under partial oxidation is very unstable and difficult to control the process due to exothermic reaction. (b) Such type of carbonization process cannot be automated due to the varying nature and quality of the raw material and hence relies more on the skill and experience of the operator. (c) Partial oxidation of solid organic materials results in emission of wide range of toxic gases which are extremely difficult to treat. (d) Yield of the raw materials to the finished products (i.e. carbon) is high and will not be consistent always. (e) Ash content of the carbon will be high (due to processing of material under partial oxidation) resulting in lower quality and lower physical strength of the carbon product. (f) Direct conversion of the solid organic materials to activated carbon is very difficult under exothermic conditions.